Why would you 'underclock' your GPU memory>

[Chick]

I was wondering why you guys do this, isn't overclocking going to get your better performance?

Also, how do I flash my 5830s through Linux? Or would I need windows to do this job?

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[eskil]

only gpu clock counts towards hashing power. memory clock is irrelevant.
you can underclock your memory to save some degrees temparature that you may better spend on some gpu clock OC

[faille]

Mostly a heat issue, some people also report gains in hashing by reducing memory clock, but it depends on the cards. Some cards get worse with reduced memory clocks.

[CentroniX]

Mineing requires pure computations; theres not a lot to store in memory. Under clocking your memory reduce heat, which allows you to over clock the GPU even more without your temps rising further.

As far as flashing, the quick answer is you'll need windows. You can install WINE, the windows emulator, and run a windows application within Linux, but it's risky. If it fails during a flash, you can brick your card. There's a thread here somewhere about booting off a freedos USB stick, grabbing the bios, putting the USB stick in a windows box to edit the bios, then reflash via freedos again to flash the card. probably your best bet.

[supa]

I was wondering why you guys do this, isn't overclocking going to get your better performance?

Also, how do I flash my 5830s through Linux? Or would I need windows to do this job?

In my usable range (150-1125), I actually get a performance decrease at 150, increase at 300, and decrease above.  I dunno.

No, you don't need windows to flash.  There are guides out there on how to use unetbootin to create a FreeDOS bootable thumbie.  Put atiflash.exe on there.

Use atiflash.exe to dump your existing BIOS.

Boot back into Linux, set up Wine.  Run the "Radeon Bios Editor" in Wine (you have to get vb6 with winetricks or whatever).  Edit the BIOS you dumped with atiflash.exe.  Copy that to the thumbie.

Boot off the thumbie, write the BIOS back with atiflash.exe.

Reboot to Linux - you're done.

[Chick]

only gpu clock counts towards hashing power. memory clock is irrelevant.
you can underclock your memory to save some degrees temparature that you may better spend on some gpu clock OC

That's weird, I tried lowering my memory clock to 900 (minimum) and the performance lowered 10-20 mh / sec. As soon as I put them back up, they returned to what they previously were.

[supa]

That's weird, I tried lowering my memory clock to 900 (minimum) and the performance lowered 10-20 mh / sec. As soon as I put them back up, they returned to what they previously were.

See my post above.

Fiddle with it - for whatever odd reason, one of my cards seems to have "sweet spots" (I'm sure yours does, too).

Here are some examples from one of my cards -

900 CPU, 220 Memory - 5 MHs more than if I put the memory clock at 150 *or* 1125.

1000 CPU, 300 Memory - 15 MHs more than if I put the memory clock at 1125 or 200.

1025 CPU, 200 Memory - any other settings crashes the card .